(A) is entitled to monthly insurance benefits under section 402 of this title , would be entitled to those benefits except that he has not filed an application therefor (or application has not been made for a benefit the entitlement to which for any individual is a condition of entitlement therefor), or would be entitled to such benefits but for the failure of another individual, who meets all the criteria of entitlement to monthly insurance benefits, to meet such criteria throughout a month, and, in conformity with regulations of the Secretary, files an application for hospital insurance benefits under part A of subchapter XVIII,
(B) is a qualified railroad retirement beneficiary, or
(C) (i) would meet the requirements of subparagraph (A) upon filing application for the monthly insurance benefits involved if medicare qualified government employment (as defined in section 410(p) of this title ) were treated as employment (as defined in section 410(a) of this title ) for purposes of this subchapter, and (ii) files an application, in conformity with regulations of the Secretary, for hospital insurance benefits under part A of subchapter XVIII,